The invention set forth in this specification pertains to new and improved fastener structures. Specifically it pertains to fastener structures utilizing an adhesive which are especially adapted for use with various types of laminated members but which are also capable of other utilizations.
The word "fastener" is a rather broad, generic term utilized so as to designate any device intended to be utilized in securing any article in place or to another article. As this word is used in this specification it is intended to designate various common fasteners or fastener structures such as grommets, rivets, nut elements, reinforcements and the like which are utilized in connection with a member such as a panel, a fabric, or the like for any of a wide variety of different, diverse purposes. Many different fastener structures for such purposes are, of course, known and utilized. Indeed various different types of such fasteners have probably been utilized since the advent of civilization. Many different specific types of fastener structures have been developed for different specific utilizations.
At the present time so-called "laminated" members or structures consisting of a plurality of fibers disposed in one or more layers into a single member are being increasingly utilized in various "critical" type applications. Normally the fibers in such structures are bonded together or held together by the use of an appropriate polymer or polymer system. As an example of this at the present time members are being increasingly utilized in aerospace applications which include a plurality of graphite fibers oriented in a desired manner and secured together by an epoxy polymer composition. Normally the surfaces of such members are not completely smooth because of the construction of such members.
Several difficulties have been encountered in connection with the utilization of known fasteners in connection with such laminated members. At times a problem has been encountered in adequately securing such fasteners to such members so that there is no reasonable chance of relative motion between these fasteners and these members. Efforts have been made to remedy this problem through the utilization of a thermosetting material secured to at least one surface of a fastener designed to be in contact with a member. Expedients of this type are considered to be and to have been undesirable because of economic considerations.
In effect, time is money in manufacturing operations. Generally speaking it is extremely desirable to be able to install a fastener in such a manner that the fastener is incapable of relative movement with respect to the member upon which it is installed within a minimum time. It is considered that prior fasteners or fastener structures related to the fastener structures of the present invention have not been desirable because of either problems of adequate engagement with a member used with such a structure and/or because of the time required to satisfactorily install such structures in operative positions.